The prupose of this project is to conduct research in statistical methods and computer techniques with particular emphasis on those appropriate to the analysis of data from clinical and diagnostic trials and epidemiological studies of cancer. Many of the problems studied under this project arise from the consultative activities of the Section. In the past year this research has included new work on the theory of survival analysis, sequential monitoring of clinical trials, precision of adjusted survival curves, study of methods for putting confidence limits on estimates of the median survival time, work on fitting survival models incorporating covariate information, inquiry into design considerations for secondary treatments in randomized clinical trials, the use of matching on time-dependent covariates in evaluating the importance of certain events occurring during follow-up studies, adaptations of logistic regression for sequences of binary responses, and a study of multiple comparisons in two-way tables which may be helpful in interpreting subset analyses in epidemiologic studies. Further refinements have been added to the interactive data analysis programs developed in this Section which permit rapid and sophisticated analyses required for effective consulting.